Question

Prove that : $(1-co{s}^{2}A).cose{c}^{2}A=1$.

Answer 1

Identity : ${\sin }^{2}A+{\cos }^{2}A=1$

LHS $=(1-{\cos }^{2}A)cose{c}^{2}A$

$={\sin }^{2}A\times \frac{1}{{\sin }^{2}A}$

$=1$

$=RHS$

Hence proved